protected function findDuplicates(FcForm $fc_form, &$fields)
 {
     foreach ($fc_form->getFcFields() as $fc_field) {
         if ($fc_field->isCustom()) {
             $this->findDuplicates($fc_field->getCustomWidget(), $fields);
         } else {
             if (!in_array($fc_field->getName(), $fields)) {
                 $fields[] = $fc_field->getName();
             } else {
                 throw new \Exception($this->translator->trans('fc.constraint.admin.not_unique_field_name', array(), 'validators'));
             }
         }
     }
 }